Wear of polycrystalline boron nitride tool during the friction stir welding of steel

The wear issue of a polycrystalline boron nitride (PCBN) tools during the friction stir welding of two grades of steel, DH36 and EH46, was studied. Two welding traverse and tool rotational speeds were used when welding the DH36 steel. A low tool speed (200RPM, 100 mm/min) and a high tool speed (550RPM, 400 mm/min) were denoted by W1D and W2D, respectively. Nine welding conditions were applied to the welding of EH46 steel plate including seven plunge/dwell trials (W1E–W7E) and two steady-state trials (W8E and W9E). SEM–EDS and XRD tests were applied in order to reveal the boronitride (BN) particles inside the welded joints, and the percentage (%) of BN was calculated according to the standard quantitative metallographic technique. The findings showed that tool wear increases when the tool rotational speed increases as a result of binder softening which is a function of the peak temperature (exceeds 1250 °C) at the tool/workpiece interface. When considering the EH46 steel trials, it was found that an increase in the tool traverse speed in friction stir welding caused a significant tool wear with 4.4% of BN in the top of the stirred zone of W9E compared to 1.1% volume fraction of BN in W8E which was attributed to the higher thermomechanical action on the PCBN tool surface. Tool wear was also found to increase with an increase in tool plunge depth as a result of the higher contact between the surface of friction stir welding tool and the workpiece

The development of path integration: combining estimations of distance and heading

Efficient daily navigation is underpinned by path integration, the mechanism by which we use self-movement information to update our position in space. This process is well-understood in adulthood, but there has been relatively little study of path integration in childhood, leading to an underrepresentation in accounts of navigational development. Previous research has shown that calculation of distance and heading both tend to be less accurate in children as they are in adults, although there have been no studies of the combined calculation of distance and heading that typifies naturalistic path integration. In the present study 5-year-olds and 7-year-olds took part in a triangle-completion task, where they were required to return to the startpoint of a multi-element path using only idiothetic information. Performance was compared to a sample of adult participants, who were found to be more accurate than children on measures of landing error, heading error, and distance error. 7-year-olds were significantly more accurate than 5-year-olds on measures of landing error and heading error, although the difference between groups was much smaller for distance error. All measures were reliably correlated with age, demonstrating a clear development of path integration abilities within the age range tested. Taken together, these data make a strong case for the inclusion of path integration within developmental models of spatial navigational processing

The relationship between lower body stiffness and injury incidence in female netballers

© 2017 Informa UK Limited, trading as Taylor & Francis Group. The aim of this study was to provide contemporary information on injury rates in an elite and sub-elite netball population and to explore the relationship between lower body stiffness and lower body injuries. One elite and two sub-elite teams of female netballers (n = 29) performed the vertical hop test to assess active lower body stiffness (Kvert) and myometry to assess quasi-static stiffness. Lower body injuries were monitored via self-reporting and liaison with physiotherapists. Twelve lower body non-contact injuries were sustained by 10 players, equating to 11.29 lower body injuries per 1,000 exposure hours. The most commonly injured sites were the calf (33%) and ankle (25%). No significant differences between Kvert of injured and non-injured players were reported, however, injured elite players recorded significantly higher season mean quasi-static stiffness in the soleus (p = 0.037) and Achilles (p = 0.004) than non-injured elite players. Elite and sub-elite netball players recorded a higher injury incidence than previous reports of injuries in recreational netballers. Within the constraints of the study, relatively high stiffness of the soleus and Achilles appears to be related to lower body non-contact injury incidence in female netballers, particularly at the elite level. These results provide a basis for development of injury prevention strategies

Image informatics strategies for deciphering neuronal network connectivity

Brain function relies on an intricate network of highly dynamic neuronal connections that rewires dramatically under the impulse of various external cues and pathological conditions. Among the neuronal structures that show morphologi- cal plasticity are neurites, synapses, dendritic spines and even nuclei. This structural remodelling is directly connected with functional changes such as intercellular com- munication and the associated calcium-bursting behaviour. In vitro cultured neu- ronal networks are valuable models for studying these morpho-functional changes. Owing to the automation and standardisation of both image acquisition and image analysis, it has become possible to extract statistically relevant readout from such networks. Here, we focus on the current state-of-the-art in image informatics that enables quantitative microscopic interrogation of neuronal networks. We describe the major correlates of neuronal connectivity and present workflows for analysing them. Finally, we provide an outlook on the challenges that remain to be addressed, and discuss how imaging algorithms can be extended beyond in vitro imaging studies

Interleukin-6 gene (IL-6): a possible role in brain morphology in the healthy adult brain

Background: Cytokines such as interleukin 6 (IL-6) have been implicated in dual functions in neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative and neuroproliferative properties of cytokine genes. In this study the potential dual role of several IL-6 polymorphisms in brain morphology is investigated. Methodology: In a large sample of healthy individuals (N = 303), associations between genetic variants of IL-6 (rs1800795; rs1800796, rs2069833, rs2069840) and brain volume (gray matter volume) were analyzed using voxel-based morphometry (VBM). Selection of single nucleotide polymorphisms (SNPs) followed a tagging SNP approach (e.g., Stampa algorigthm), yielding a capture 97.08% of the variation in the IL-6 gene using four tagging SNPs. Principal findings/results: In a whole-brain analysis, the polymorphism rs1800795 (−174 C/G) showed a strong main effect of genotype (43 CC vs. 150 CG vs. 100 GG; x = 24, y = −10, z = −15; F(2,286) = 8.54, puncorrected = 0.0002; pAlphaSim-corrected = 0.002; cluster size k = 577) within the right hippocampus head. Homozygous carriers of the G-allele had significantly larger hippocampus gray matter volumes compared to heterozygous subjects. None of the other investigated SNPs showed a significant association with grey matter volume in whole-brain analyses. Conclusions/significance: These findings suggest a possible neuroprotective role of the G-allele of the SNP rs1800795 on hippocampal volumes. Studies on the role of this SNP in psychiatric populations and especially in those with an affected hippocampus (e.g., by maltreatment, stress) are warranted.Bernhard T Baune, Carsten Konrad, Dominik Grotegerd, Thomas Suslow, Eva Birosova, Patricia Ohrmann, Jochen Bauer, Volker Arolt, Walter Heindel, Katharina Domschke, Sonja Schöning, Astrid V Rauch, Christina Uhlmann, Harald Kugel and Udo Dannlowsk

Peripheral arterial volume distensibility changes with applied external pressure: significant difference between arteries with different compliance

This study aimed to quantify the different effect of external cuff pressure on arterial volume distensibility between peripheral arteries with different compliance. 30 healthy subjects were studied with the arm at two positions (0° and 45° from the horizontal level) to introduce different compliance of arteries. The electrocardiogram and finger and ear photoplethysmograms were recorded simultaneously under five external cuff pressures (0, 10, 20, 30 and 40 mmHg) on the whole arm to obtain arterial volume distensibility. With the applied external cuff pressures of 10, 20, 30 and 40 mmHg, the overall changes in arterial volume distensibility referred to those without external pressure were 0.010, 0.029, 0.054 and 0.108% per mmHg for the arm at the horizontal level, and 0.026, 0.071, 0.170 and 0.389% per mmHg for the arm at 45° from the horizontal level, confirming the non-linearity between arterial volume distensibility and external pressure. More interestingly, the significant differences in arterial volume distensibility changes were observed between the two arm positions, which were 0.016, 0.043, 0.116 and 0.281% per mmHg (all P < 0.01). Our findings demonstrated that arterial volume distensibility of peripheral arm arteries increased with external pressure, with a greater effect for more compliant arteries

Modelling the public health impact of male circumcision for HIV prevention in high prevalence areas in Africa

Background: Recent clinical trials in Africa, in combination with several observational epidemiological studies, have provided evidence that male circumcision can reduce HIV female-to-male transmission risk by 60% or more. However, the public health impact of large-scale male circumcision programs for HIV prevention is unclear. Methods: Two mathematical models were examined to explore this issue: a random mixing model and a compartmental model that distinguishes risk groups associated with sex work. In the compartmental model, two scenarios were developed, one calculating HIV transmission and prevalence in a context similar to the country of Botswana, and one similar to Nyanza Province, in western Kenya. Results: In both models, male circumcision programs resulted in large and sustained declines in HIV prevalence over time among both men and women. Men benefited somewhat more than women, but prevalence among women was also reduced substantially. With 80% male circumcision uptake, the reductions in prevalence ranged from 45% to 67% in the two "countries", and with 50% uptake, from 25% to 41%. It would take over a decade for the intervention to reach its full effect. Conclusion: Large-scale uptake of male circumcision services in African countries with high HIV prevalence, and where male circumcision is not now routinely practised, could lead to substantial reductions in HIV transmission and prevalence over time among both men and women

The effect of water-based plyometric training on vertical stiffness and athletic performance

© 2018 Sporri et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Since higher vertical stiffness is related to superior athletic performance, training has traditionally been aimed at augmenting this variable to enhance neuromuscular output. However, research has linked elevated stiffness with increased injury risk, therefore, this study examined the effect of a novel training intervention on vertical stiffness and athletic performance. Vertical stiffness, jump performance and athletic performance were assessed in two randomly allocated groups, prior to, and following, an eight-week period. One group was exposed to a training intervention involving aqua-based plyometrics (n = 11) over the 8 weeks while the other acted as a control group (n = 9). The training intervention involved hopping, jumping and bounding in water at a depth of 1.2m whilst control participants performed their normal training. There were no significant changes in vertical stiffness in either group. Countermovement jump height and peak power significantly increased within the aqua plyometric group (p < 0.05). Athletic performance markers improved in the aqua plyometric group as measured using an agility and a 5-bound test exhibiting superior values at the post-test (p < 0.05). The results suggest that an aqua plyometric training program can enhance athletic performance without elevating stiffness. The increase in athletic performance is likely due to a reduction in ground reaction forces created by the buoyancy of the water, causing a shorter amortization phase and a more rapid application of concentric force. The findings from this study can inform exercise professionals and medical staff regarding the ability to enhance neuromuscular performance without elevating vertical stiffness. This has implications for improving athletic performance while concurrently minimising injury risk

Enteric Pathogens in Stored Drinking Water and on Caregiver's Hands in Tanzanian Households with and without Reported Cases of Child Diarrhea.

Diarrhea is one of the leading causes of mortality in young children. Diarrheal pathogens are transmitted via the fecal-oral route, and for children the majority of this transmission is thought to occur within the home. However, very few studies have documented enteric pathogens within households of low-income countries. The presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed in hand rinses and household stored drinking water in Bagamoyo, Tanzania. Using a matched case-control study design, we examined the relationship between contamination of hands and water with these markers and child diarrhea. We found that the presence of ECVG in household stored water was associated with a significant decrease in the odds of a child within the home having diarrhea (OR = 0.51; 95% confidence interval 0.27-0.93). We also evaluated water management and hygiene behaviors. Recent hand contact with water or food was positively associated with detection of enteric pathogen markers on hands, as was relatively lower volumes of water reportedly used for daily hand washing. Enteropathogen markers in stored drinking water were more likely found among households in which the markers were also detected on hands, as well as in households with unimproved water supply and sanitation infrastructure. The prevalence of enteric pathogen genes and the human-specific Bacteroidales fecal marker in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. Better stored water quality among households with diarrhea indicates caregivers with sick children may be more likely to ensure safe drinking water in the home. Interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30